1. Field of the Invention
The present invention is directed to providing a process for imparting smoothness, body and a permanent wave pattern to hair of varying natural curl levels, particularly multi-textured hair. More specifically, the present invention is directed to a multi-step hair treatment process whereby an alkaline hydroxide (preferably sodium hydroxide) is first used to smoothen naturally curly hair, then, prior to neutralization, a thioglycolate reducing agent (preferably ammonium thioglycolate) is used to create a new wave pattern in the hair.
2. Description of the Relevant Art
Conventional hair treatment products based upon compositions containing thioglycolates, sulfites, or alkali metal hydroxides, such as sodium hydroxides, have been widely used to permanently straighten tightly curled hair, especially to straighten the hair of people of African descent. Of these products, the thioglycolate compositions and the sulfite compositions which have been commercially marketed have been relatively ineffective, with the hair in many cases reverting at least partially to the original unstraight form. While very effective in producing the desired straightening effect, sodium hydroxide compositions are very harsh to both the scalp and the hair, and the use of such compositions has resulted in numerous instances of scalp irritation and/or burning, and has also resulted in a substantial reduction in the strength of the treated hair, and even, in some instances, considerable hair breakage and loss.
While thioglycolate compositions have been relatively ineffective in straightening tightly curled hair, they have been very effective in and are widely used for, adding curl or permanent waves to straight hair, such as Caucasian hair. However, because the wave imparted by the thioglycolate compositions relaxes over time, these products must be repeatedly used on naturally straight hair. This recurring use and, from time to time, overuse, can cause the hair to become frizzy and damaged.
While products such as those mentioned above have been formulated for tightly curled and straight hair, there has not previously been much attention given to the special needs of multi-textured hair, that is, hair that is a combination of frizzy, straight, and curly.
Multi-textured hair, to which the present invention is particularly directed, when processed with a conventional chemical straightening treatment, is left straight and limp. When processed with a conventional texturizing treatment, such as that disclosed in U.S. Pat. No. 4,361,157, it is still left with an uncontrolled curl pattern and little body. When processed (wrapped or rodded) as a regular cold body wave, the hair is left with more frizz. Multi-textured hair types can be found in all races, in the descendants of Caucasians, Indians, Asians and Africans. The process of the present invention allows one to understand the general make-up of hair and the link which ties all hair types together, thus allowing the stylist to work on all hair textures using a unique combination of chemical hair treatments.
Numerous U.S. Patents are directed to hair straightening and hair waving. Patents with some relevance to the subject matter of the present invention include the following:
U.S. Pat. No. 4,361,157 describes a method for producing waves in tightly curled hair by a process of applying a relaxer followed by a neutralizer-shampoo after combing.
U.S. Pat. No. 4,793,994 teaches an aqueous relaxing composition using N-alkyl lactams and thioglycolate acid.
U.S. Pat. No. 5,241,973 describes an improved cold wave formulation using polymeric mixed disulfides.
U.S. Pat. No. 4,982,750 describes a method for relaxing and recurring tightly curled or kinked hair using monoethanolamine thioglycolate and a heat-generating composition.
U.S. Pat. Nos. 4,303,085 and 4,314,572 describe the use of guanidine hydroxides to permanently alter hair structure.
None of the cited patents teach the combination of the two separate processes of sodium hydroxide straightening with ammonium thioglycolate waving in one system, nor do they teach sodium hydroxide relaxation followed by a process other than neutralization.